configure: silence glib unknown attribute __alloc_size__

The glib headers use GCC attributes.  Unfortunately the __GNUC__ and
__GNUC_MINOR__ version macros are also defined by clang, but clang
doesn't support the same attributes as GCC.

clang 3.5.0 does not support the __alloc_size__ attribute:

  c047507a9a

The following warning is produced:

  gstrfuncs.h:257:44: warning: unknown attribute '__alloc_size__' ignored [-Wunknown-attributes]
        G_GNUC_MALLOC G_GNUC_ALLOC_SIZE(2);
          gmacros.h:67:45: note: expanded from macro 'G_GNUC_ALLOC_SIZE'
                #define G_GNUC_ALLOC_SIZE(x) __attribute__((__alloc_size__(x)))

This patch checks whether glib headers cause warnings and disables
-Wunknown-attributes if it is able to.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1427324259-1481-4-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
John Snow 2015-03-25 18:57:38 -04:00 committed by Stefan Hajnoczi
parent 93b2586922
commit bbbf2e04e5

12
configure vendored
View file

@ -2807,6 +2807,18 @@ if ! $pkg_config --atleast-version=2.38 glib-2.0; then
glib_subprocess=no
fi
# Silence clang 3.5.0 warnings about glib attribute __alloc_size__ usage
cat > $TMPC << EOF
#include <glib.h>
int main(void) { return 0; }
EOF
if ! compile_prog "$glib_cflags -Werror" "$glib_libs" ; then
if cc_has_warning_flag "-Wno-unknown-attributes"; then
glib_cflags="-Wno-unknown-attributes $glib_cflags"
CFLAGS="-Wno-unknown-attributes $CFLAGS"
fi
fi
##########################################
# SHA command probe for modules
if test "$modules" = yes; then